1. Field of the Invention
The present invention relates to a label for re-closable packages, having an application side on which a layer of self-adhesive glue is spread for application to a surface of a re-closable package to achieve a predetermined adhesive strength.
More particularly, the label is of the type which is made available on a siliconized backing, for example, a continuous backing tape.
2. Description of the Prior Art
Self-adhesive labels of the type specified are used, for example, for re-closable packages for food products such as bakery products, for example, toasted bread slices, biscuits and the like, the contents of which are not eaten all at once. Until the contents are completely used up, the package therefore has to be re-closable by means of the same label, to protect the food product from air, odours, etc., in order to keep its physical and organoleptic characteristics unchanged.
The self-adhesive label is therefore intended to be detached by the consumer when the re-closable package is opened, for subsequent re-use by the consumer to reclose or seal the package.
Labels of the type specified have a considerable disadvantage, however.
The strength of the adhesion of the layer of glue to a surface depends mainly upon the physical characteristics, such as the roughness, the porosity, etc., of the surface, upon the length of time which elapses between the application and the first use, and upon the temperature at which the reclosable packages are stored.
The variability of the last two parameters mentioned, together with the type of paper which is usually used to manufacture re-closable packages for bakery products and the like, means that it is impossible to predict with certainty the adhesive strength between the layer of self-adhesive glue and the surface of the re-closable package to which it is applied.
Naturally, to prevent the packages from opening spontaneously during transportation and display for sale, self-adhesive glues which achieve good adhesive strength between the layer of glue and the package, that is, between the label and the package, tend to be used, in any case.
The satisfaction of this requirement, however, causes an undesirable number of the aforesaid labels to tear the paper surface to which they are applied during their removal from the package in order to open it, rendering further use of the label impossible and irreparably damaging the package because the layer of glue adheres tightly to the package with too great an adhesive strength.